Getting Missional Online

Well I just read about this site called Favorville and decided to check it out. Essentially it is a place where people come to offer favours and seek favours. Guess what, they have a Dublin, Ireland location. After checking it out it seems to not be specific to Dublin, Ireland however. That said, the site is still in its beta phase and I'm sure they'll fix it. It's kinda like a craigslist for favours. Both of these sites rely on web-community for existence. I wonder what the possibilities are for missional movements within these (and other) sites?